I think that's looking too narrowly at the problem. For example, for years Spotify used P2P tech to reduce demand on their servers - nothing stops a Youtube alternative from doing the same.
That wouldn't stop anyone with deep pockets(Microsoft, Apple) from taking a shot. Netflix or Twitch may be in a good position to adopt departing YouTubers, as well.
If the content creators leave YouTube, their audiences will follow them. It's definitely an opportunity for someone, the question is just "who?"
To whatever startup(or other business) that successfully takes advantage of the market opening that Google has created by tightening the screws?